I claim the ornamental design for a sports helmet, as shown and described.
FIG. 1 is a front, side perspective view of a sports helmet;
FIG. 2 is a side view of the sports helmet of FIG. 1; and,
FIG. 3 is a front view of the sports helmet of FIG. 1.
The dashed lines which illustrate environmental elements and the dashed/dotted lines which represent boundary lines form no part of the claimed design.